The objective of this study is to examine the potential of cost reduction and factors affecting production cost of Korean farmers. First, the study estimates technical efficiency, allocation efficiency, and cost efficiency of Korean farmers using DEA. Then, Tobit regressions are conducted to identify factors affecting each of the three efficiency scores. The study uses the Farm Household Economy Survey data from the Korean National Bureau of Statistics for the period from 2008 to 2012. Results from DEA show that overall, technical and cost efficiency scores are low, which suggests a great potential of cost reduction for Korean farmers. The results also show relatively large differences in efficiency scores across provinces. Tobit results suggest that farm size, number of family members, operation costs, and invested capital amount are major factors affecting farm efficiencies.

This paper describes study of the converter topologies for a low-cost, high-efficiency switched reluctance motor(hereafter abbreviated as SRM) drive. The considered converter employs two-switch split AC supply configuration. The converter preserves a single switch per phase as well as a single phase-leg rectifier circuit realizing the fewest component count to achieve a highly cost effective solution for two-phase SRM drive. Comparative study between the considered converter and other converters are provided. Analysis of the modes of operation and mathematical modeling are also provided. Analysis and simulation results are provided to validate the converter. The considered split AC converter can be a strong candidate for low-cost applications such as power tools, fans, and small appliances where both cost and efficiency are most valued.

「Special Act for the Safety Control of Public Structures」is for the periodical inspection and maintenance on the main structures. It is based on the reactive measures for the found faults and the maintenance budget is allotted with a ceiling. Therefore decision makers cannot establish long-term strategies and connot consider the serviceability from a user's point of view. The infrastructure maintenance system has to be renewed considering for the efficiency in the face to the rapid increase of the rate of deteriorated facilities.